Antimutagenic effects of ethanol and aqueous extracts of Avicennia marina leaves on Salmonella typhimurium TA100 bacterium

Background: Avicennia marina (Forssk.) Vireh. or gray mangrove tree, belonging to the family Avicenniaceae, has long been used as a remedy to treat ulcers and skin diseases. In the present study, the antimutagenic activities of young and mature leaf extracts of Avicennia marina against the mutated bacterium Salmonella typhimurium TA100 were investigated. Materials and Methods: In this experimental study, the bacterial strain was checked for the intended genotypes. Leaves were isolated, dried, and chopped finely using a blender and they were extracted with 80% ethanol or water using a Soxhlet extractor. Metabolic activation was prepared from male rat homogenized liver. Antimutagenic effect of the extracts was tested using Ames test in the presence of a mutagen. Results: The number of mutant colonies decreased in the presence of both ethanol and water extracts with (+S9) and without (-S9) metabolic activation. The ethanolic extract exhibited a higher antimutagenic activity than the water extract. There were no inter-assay differences in the presence and absence of the S9 mixture. The highest (71%) and the lowest (24%) inhibition rates of Salmonella typhimurium TA100 bacterial growth were observed with the ethanolic extract of mature leaves from Bordekhon region and the aqueous extract of young leaves from Assaluyeh region, respectively. Conclusion: The findings of the present study suggest that Avicennia marina (Forssk) Vireh. leaf extracts may contain bioactive compounds that can inhibit mutation, and that biotic and/or abiotic stress might have an effect on the antimutagenic potential of these leaf extracts in the two regions.